1. Field of the Invention
The present invention relates to a slide fastener with a separable end stop, which is attached by ultrasonic or high-frequency welding to the opening of an article such as a raincoat, anorak, or bag made of a sheet of thermoplastic resin material.
2. Description of the Prior Art
In a conventional slide fastener which has a separable end stop, it is well known to facilitate stable attachment of the separable end stop to a slide fastener, easy operation of the separable end stop upon engagement or disengagement thereof, and reinforcement of attachment condition between lower end of a slide fastener and a separable end stop by providing a separable end stop attachment portion located at one end of the fastener tape with a reinforcing member.
In a case of a slide fastener which has a separable end stop and which is formed from a sheet of thermoplastic synthetic resin material such as polyvinyl chloride, a reinforcing member is also attached to a separable end stop attachment portion. When attaching such slide fastener to, for example, a raincoat made from a sheet of synthetic resin material, thermal bonding means is utilized.
The reinforcing member has a multi-layer structure consisting of a bonding layer having a low enough melting point to enable it to be bonded to the fastener tape, and a reinforcing layer having a melting point which is higher than that of the bonding layer. Since the reinforcing layer is generally formed of a film which has a relatively high melting point, such as Nylon 6 or Nylon 66, or a taffeta using threads of such a material, the portion of the fastener tape excluding the reinforcing member can be integrally welded to an attachment portion of the article by an ultrasonic or high-frequency welder, but the conventional slide fastener has a disadvantage in that it is impossible to completely weld to the article the portion of the fastener tape on which the reinforcing member is mounted.
In other words, in a conventional slide fastener, the reinforcing member of the separable end stop attachment portion, which should be most firmly attached to the article, is not welded to the article. Furthermore, since the article is generally formed of a slippery unwoven material made of a thermoplastic resin, the non-welding of the reinforcing member to the article occasionally causes relative slippage between the article and the member. Consequently, when the reinforcing member and the article are held together between the fingers to manipulate the separable end stop, this slippage means that the movements of the fingers cannot be conveyed to the separable end stop as intended, resulting in the incomplete insertion of the butterfly pin or the forcible pulling-up of the slider.
Thus, the slide fastener with the separable end stop provided by the prior art has problems in that, due to the incomplete bonding between the reinforcing member and the article, the separable end stop cannot be smoothly manipulated. Furthermore, if the fastener elements are engaged imperfectly by applying excessive force, these elements will be disengaged afterward.